Polyol Block Copolymer Synthesis with Two-Stage CO2 Incorporation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods using a DMC catalyst for producing polyether carbonate polyols are limited in CO2 incorporation, requiring high pressures and cannot produce low molecular weight polyols with substantial CO2 content, and result in polymers with uneven linkage distribution and stability.
Innovation Solution
A two-reactor system is employed, using a carbonate catalyst in the first reactor to produce a polycarbonate polyol, followed by a DMC catalyst in the second reactor, allowing for increased CO2 content and optimized reaction conditions for each catalyst, resulting in a polyol block copolymer with high carbonate content and improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a DMC catalyst is used alone for producing polyether carbonate polyols, then the polymerization reaction can proceed, but the CO2 incorporation is limited to around 50% and high pressures (more than 40 bar) are required
Solution Approach 1:
The patent divides the polymerization process into two separate reactions using two different catalysts: first a carbonate catalyst to produce polycarbonate polyol with high CO2 incorporation, then a DMC catalyst to produce the final polyether carbonate polyol. This segmentation allows each catalyst to operate under optimized conditions, enabling high CO2 content at lower pressures.
Solution Approach 2:
The patent performs preliminary action by first producing polycarbonate polyol with high CO2 incorporation using a carbonate catalyst before adding the DMC catalyst. This pre-incorporation of CO2 into the polymer backbone allows the final product to achieve high CO2 content without requiring high pressures during the DMC catalyzed step.
2Quantity of substance
If a DMC catalyst is used alone, then polymerization can occur, but low molecular weight polyols cannot be produced with substantial CO2 content
Solution Approach 1:
The patent segments the synthesis into two distinct stages: first producing low molecular weight polycarbonate polyol with high CO2 content using a carbonate catalyst, then using this as a starter for DMC-catalyzed polyether formation. This allows precise control over molecular weight and CO2 content that cannot be achieved with a single catalyst system.
3Stability of the object's composition
If a DMC catalyst is used alone, then polyether carbonate polyol can be produced, but the polymer structure has ether groups concentrated in the centre and carbonate groups at terminals, which is not advantageous for stability
Solution Approach 1:
The patent applies local quality by creating a block copolymer structure where the polycarbonate block (with high carbonate linkage content) forms the core and polyether blocks form the terminals. This non-uniform distribution places the more stable carbonate groups in the polymer core, improving overall thermal and chemical stability while maintaining ease of synthesis.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process enables the production of low molecular weight polyols with significant CO2 content under mild pressures, achieving polymers with narrower molecular weight distribution and improved thermal and chemical stability, suitable for high-performance polyurethanes.
Implementation Method 1
a first reaction is the reaction of a carbonate catalyst with CO2 and epoxide, in the presence of a starter and/or solvent to produce a polycarbonate polyol copolymer
Implementation Method 2
the second reaction is the reaction of a DMC catalyst with the polycarbonate polyol compound of the first reaction and epoxide to produce a polyol block copolymer
Data Source
AI summary
A process for producing a polyol block copolymer in a multiple reactor system including a first and second reactor in which a first reaction takes place in the first reactor and a second reaction takes place in the second reactor. The first reaction is the reaction of a carbonate catalyst with CO2 and epoxide, in the presence of starter and/or solvent to produce polycarbonate polyol copolymer and the second reaction is the reaction of DMC catalyst with the polycarbonate polyol compound of the first reaction and epoxide to produce polyol block copolymer. The product of the first reaction is fed into the second as crude reaction mixture, the epoxide and the polycarbonate polyol compound of the first reaction are fed in a continuous or semi-batch manner, and/or the product of the first reaction has neutral or alkaline pH on addition to the second. The invention further relates to the copolymers and products incorporating such copolymers.